Calcium Polycarbophil U.S.P. ("CPC") is the calcium salt of polycarbophil, which is polyacrylic acid cross-linked with divinyl glycol. Pharmaceutical grade CPC is a water insoluble, hydrophilic, swellable polymer capable of absorbing approximately 35 times its weight of water. The polymer is available from different suppliers in different physical grades which are primarily based on particle size and particle characteristics.
Based on its absorbing and swelling characteristics, CPC is used as a fecal regulator, functioning both as a laxative and anti-diarrheal. In the former case, it draws water to the intestine, swells to form bulk, and causes laxation. In the latter case, it absorbs excess water in the intestine to improve the consistency of watery bowel movements and decrease frequency of bowel movements, thus providing control of diarrhea.
Diarrhea is a major cause of death in children around the world, especially in underdeveloped countries. Even in the United States, diarrhea resulting from both unknown causes and from association with infections, food disorders and allergies represents a significant medical problem.
Diarrhea may be of the acute or chronic type. Although acute diarrhea may be caused by enteric infections, such as dysentery, it is likely that most cases of acute diarrhea are due to abuse of cathartics, ingestion of irritant food, or to minor upsets such as nervous indigestion, acute febrile illnesses or simple fatigue. The etiology in any given case is frequently unknown because of the difficulty of clinically distinguishing one type from another. Symptomatic treatment of the condition, therefore, is usually undertaken without diagnosis. Chronic diarrhea may result from ulcerative colitis, regional inflammation of the bowel, neoplasm, and the like. In such cases, symptomatic treatment is also usually necessary since the cause is often not known or is difficult or impossible to eliminate.
It is well known that diarrheal states are widely prevalent. Similarly, the discomfort and the danger often associated with this condition are also common knowledge. The superimposition of these facts on the difficulty for some people, particularly young children, to ingest existing anti-diarrheal agents emphasizes the tremendous need for an easily administered, effective agent for the symptomatic management of this disease.
Products currently used as anti-diarrheals, available either over-the-counter (OTC) or by prescription (Rx), are primarily intended for use in adults and older children. All have documented problems with respect to side effects and adverse reactions. They are generally of two types--those which reduce intestinal motility through drug action, and those which are intended as adsorbents, primarily clays such as attapulgite and kaolin.
Calcium polycarbophil exhibits few known side effects or adverse reactions, and is apparently not absorbed from the gastrointestinal tract. It is listed as a Category I ingredient in the Tentative Final OTC Monograph.
Presently, CPC is commercially available in the form of tablets intended for swallowing or chewing. None of these forms is entirely suitable for use in pediatric applications, especially for children under six years of age. Children find chewable CPC tablets difficult to swallow because, as the tablets are chewed, they form a rubbery mass which becomes lodged in the child's teeth. The CPC tablets are also objectionable to young children because the CPC tablets have a gritty consistency leaving a poor taste and mouthfeel.
The search for a palatable form of CPC, which is suitable for use by children, has been complicated by the fact that CPC, which is insoluble in water, forms a rubbery mass upon absorbing water to its full capacity. When the particle size is reduced to nearly micron-range by conventional means, the tendency to form a rubbery mass is increased and the sharp-edged particles produce a gritty feeling in the mouth. On the other hand, when the particle size is relatively large, the product is not as rubbery, but it produces the gritty feeling in the mouth due to the sharp edges on the particles.
It was, therefore, an objective of the invention to discover methods of processing CPC to provide palatable forms which could be mixed with or sprinkled on food to allow administration to young children, as well as older children and adults.